Fluorescent Rare Earths in Semiconducting Thiospinels

Abstract

The system has been investigated with the objective of obtaining for physical studies semiconducting crystals with high rare earth content. The new compounds and , where represents the rare earths of small ionic size, have been found to have the spinel structure. Thulium was chosen as representative of this group of rare earths, and studies have been made largely in the pseudobinary system , in which complete solid solution was found to occur. Both powder samples and single crystals have been prepared, and their lattice constants and infrared fluorescence measured. The structure of has been shown to be of the normal spinel type. Weak infrared electroluminescence from single crystals has been observed.